Police officials have said the man was not a AKB48 fan but just wanted to commit an act of random murder.

AKB48 management announced Monday it was cancelling a concert at its main theatre in Tokyo's Akihabara district, as well as several other events around Japan.

The band, who are known as “idols you can meet”, are famed for their handshaking events which take place in Japan every year. Bouncers are assigned to these events to remove fans who linger, but no major attacks have been previously reported.

They hold the Guinness world record for being the world’s largest pop group, with a rotating cast of 90 women from Japan, Indonesia, China and Taiwan.

Twitter and other social networking sites were flooded with comments about the incident, many of them raising concerns about security checks.

Former AKB48 member Erena Ono tweeted: “Such an incident should never have happened. Even if they recover from their physical injuries, their emotional scars will never heal.”